Pipe slip



E. E. GREVE.

PIPE SLIP. APPLICATION FILED OCT. 11, 1921.

Patented Nov. 21, 1922.

Patented Nov. 21, 1922.

warren stares EDGAR E. GREVE, F BELLEVUE, PENNSYLVANIA.

PIPE SLIP.

Application filed October 11, 1921. Serial No. 506,986.

To all whom it may concern:

Be it known that I, EDGAR E. GREVE, a citizen of the United States,residing at Bellevue in the county of Allegheny and State oflennsylvania, have invented certain new and useful Improvements in PipeSlips, of which the following is a specification.

This invention relates to pipe slips for use 0 in conjunction withapparatus employed in handling pipe, especially rotary well drillingapparatus.

In drilling operations, particularly those using the rotary system, itis customary to .5 mount, in a ring or spider, pipe engaging slips orwedges, the function of which is to hold the string of pipe insuspension while attaching or detaching different sections to the stringwhich is being lowered or taken :0 out of the drill hole. These slipshave, to a certain extent, caused trouble due to the binding effectresulting from the manner in which the back of the slip, or that portionof the slip which is in contact with the spider, fits.

A primary object of the present invention is to so change the shape ofthe outside or back surface of the slips as to reduce the tendency tobind.

Further objects of the invention are to provide means whereby a seriesof slips may be united to facilitate handling, but will be looselyconnected in such manner as not to interfere with the proper functioningthereof, and to provide handles for each series of slips so connected,and to so.shape the slips as to facilitate the insertion of adjacentseries of slips.

My invention may be readily understood by reference to the accompanyingdrawings in which:

Fig. 1 is a top plan view of a portion of a rotary showing slips,constructed in accordance with my invention supported thereline 11-11 inI . l ig. 2 is a vertical section on of Fig.1;land

l Fig. 3 is a perspective view-of one of the sis. r Y a n the drawings,A indicates the rotatable table of a rotary or otherapparatus, and B-indicates a spideror holder supported therein having aslightly conical-or tapered central opening therein. The wallsof the central opening aregenerally circular,as shown.

The spider or holder B may be of any preferred type and need notnecessarily be used in a rotary, as slips and spiders are also used inother applications.

The several individual slips are designated by the numerals 1, 2, 3, and4., and 1, 2, 3 and 4'. Slips 1 to 4 inclusive are connected to oneseries, and slips 1' to 4' inclusive are connected in another series, sothat each series may be handled as units, as hereinafter described.

Each individual slip comprises a wedge shaped segmental body having itsgreatest thickness at the upper end thereof. The inner face a; of eachslip is curved so as to be substantially concentric with the center ofthe opening through the spider or holder, and thereby engage the outsideof a pipe passing centrally through the opening. The inner faces of theslips are serrated in a manner well understood, some ofthe slips havingvertically extending teeth to hold the pipe against rotation, while mostof the slips have horizontal serrations to hold the pipe againstlongitudinal movement.

Instead of the outside or back surfaces of the slips having a curvaturewhich conforms to the circular walls of the spider, as has heretoforebeen the practice, the outer surfaces of the individual slips are turnedto a radius shorter than the radius of the inside of the bore, as shownin a somewhat exaggerated manner in Fig. 1 of the drawings. With theslips so shaped, a full amount of contact area is obtained between thepipe and the slips, but the initial contact area between the slips andthe spider is reduced and the outer faces of the slips do not initiallycontact with the spider throughout their entire area, as do the slipsheretofore made, in which the curvature of the slip and the spiderconform. Consequently, as the slips are forced further down into thecone shaped opening by the weight of the suspended pipe, a greaterportion of the area of the slipsacrossthe periphery thereof will contactwith the spider by reason of the ever diminishing radius of curvature ofthe cone shaped opening downwardly. With the old form of slip, as hereinpreviously described, in which the center of curvature for theslips andthe spider is the same,

any slight downward movement of the slips tends to force the slipsinwardly. The periphery of each slip then has a curvature greater thanthe curvature of the opening, so that only the vertical edges of theslips contact with the walls of the opening in the spider, and theseedges have a tendency to bite intothe spider walls, while thesurface ofthe slips between the edges is naturally forced out of contact with thespider. In other words, the periphery of the old form of slip assumesthe position of a chord of a circle relatively to the inside walls ofthe spider opening, with the exception that it would becurved. With thepresent form of slip, the slip cannot move to such a position when inoperation.

It is desirable that the individual slips be relatively small andloosely connected so I that several of them can be handled as a unit. Asshown, I prefer to form two units which are substantially semi-circular.For connecting the slips, the intermediate units 2 and 3 and 2 and 3 areprovided with a projecting lug or tongue 5 at one side thereof and apocket or socket 6 at the other side, as shown in Fig. 3. In each of thetongues 5 are elongated openings 7, and passing through the body of theslips into the pockets are bolt receiving holes 8. A bolt or pin 9passed through the holes 8 and the slots or elongated openings 7 in thetongues 5 serves to connect the adjacent slips. Slips 1 and 1' areprovided with tongues 5, but it is unnecessary to form a pocket therein.The

tongues 5 on the slips 1 and 1' extend into the pocket on slip 2 and 2'respectively, and a similar pin or bolt 9 connects them. Slips 4 and 4are provided with a pocket 6 to receive the tongue 5 on slips 3 and 3respectively, but slips 4 and 4 need not be provided with the tonguesthereon. The elon gated opening 7 in the tongues 5 in the sockets 6allow for sufficient relative movement of the individual slips whenbeing forced to pipe gripping position.

he upper edges of slips 1, 1 and 4t and 4 are beveled, as indicated at10, so as to facilitate the entrance of either unit after the other hasbeen inserted in the spider. Slips 1 and 40f one unit and slips 1 and 4of the other unit have handles 11 babbitted or otherwisesecured thereto.These handles are preferably made of wire cable or rope. i

In use in a rotary, the slips are inserted into the spider after thepipe has been elevated for the purpose of attaching or detaching anothersection of pipe to the string. As the lifting and holding means at thetop of the string is released, or the string lowered a slight distance,the wedge sha ed slips will be urged down into the spider, moving themtogether and inwardly gripping the pipe. The tongue and socketconnection between the individual slips permits this relative movementthereof. By reason of the slips not conforming to the ment of the slipswithout departing from the invention and within the scope andcontemplation of the appended claims.

I claim: 1. The coinbination with a spider having an openingtherethrough, of pipe engaging slips which set into the opening, each ofsaid slips having a pipe engaging face and a spider engaging face, thesplder engaging face being designed to contact with the walls of theopening in the spider and being so shaped that its area of contact withthe spider will increase across its periphery as the slip is loweredinto the spider.

2. The combination with a. spider having an opening therethrough, thewalls of which are circular, of a series of pipe engaging slips, each ofsaid slips, having a pipe engaging face and a spider engaging surface,the spider engaging face having a curved area, the curvature of whichdiffers from the curvature of the opening in the spider.

3. The combination with a spider having a circular opening therethrough,of a series of pipe slips adapted to be inserted therein, said slipshaving pipe engaging faces and spider engaging faces, the spiderengaging faces being adapted to engage the walls of the circular openingin the spider and having a curvature struck from a radius shorter thanthe radius of the opening.

4. The combination with a spider having an opening therethrough, ofslips adapted to be inserted in the openings, tongue and socketconnections for joining a plurality of slips into units, and a handlefor each unit.

5. The combination with a spider having an opening therethrough, ofslips adapted to be inserted in the opening, tongue and socketconnections for joining a plurality of slips into units, the end slipsin each unit having beveled edges thereon to facilitate the insertion ofother units to be placed adjacent thereto, and a handle for each unit.

6. The combination with a spider having an opening therethrough, ofslips adapted to be inserted into the opening, said slips being providedwith tongue and socket connections for joining a plurality of slips intounits, said tongue and socket connection bein so arranged as to permitof a limited refit-ive movement of the individual slips in the unit. 9

7. A pipe slip construction for use in conmeans being so arranged as topermit of the nection wlth a spider comprising a plurality lateralrelative movement of the individual of slips having pipe engaging innerfaces slips in the unit. 10 and spider engaging outer faces, lateral Intestimony whereof I aflix my signa- 5 faces on the slips, andcooperating connectture.

ing means on said lateral faces for joininga plurality of slips intounits,- said connecting EDGAR E. GREVE.

